The present invention relates to sludge treatment device and, more particularly, to a sludge treatment device that turns sludge into safe to use fertilizer.
After the treatment of wastewater is performed, biosolids and the associated contaminants are removed. However, biosolids are typically high in organic content and contain moderate amounts of nutrients such as nitrogen and phosphorus. These properties make biosolids valuable as a fertilizer or soil amendment.
Biosolids are the solid, semisolid, or liquid residue generated during the biological wastewater treatment process. Biosolids that are used beneficially must be treated to reduce pathogens and vector attraction. Distribution and marketing of Class AA biosolids products is regulated by governments. Class AA biosolids are considered to be the highest quality of biosolids produced and may be utilized as fertilizer through commercial distribution and marketing.
To achieve a Class AA status, the biosolids must be treated to a level that essentially eliminates pathogens and meets strict parameter concentration limits for heavy metals. Class AA biosolids may be distributed in bulk or bagged for sale at retail garden centers. Class AA biosolids may be marketed in different physical forms, and, like traditional commercial fertilizer products, are not subject to site management restrictions if the product is registered as a fertilizer or distributed and marketed to a person or entity that will sell or give-away the biosolids or biosolids products as a fertilizer.
There are generally two classes of biosolids recognized in the United States Environmental Protection Agency's (EPA) regulations: Class B pathogen reduction standards, as set forth in 40 CFR 503, which require a fecal coliform level of less than two million most-probable-number (MPN) per gram of total solids, and Class A pathogen standards per 40 CFR 503. EPA's Class A pathogen standards requirements are met in biosolids when fecal coliform densities are less than 1,000 MPN per gram total solids; or when Salmonella densities are less than 3 MPN per four grams total solids. Additionally, enteric virus must be less than 1 plaque-forming unit per four grams of total solids, and helminth ova is less than one viable helminth ova per four grams of total solids.
Traditionally, biosolids (sludge) disposal involves trucking the sludge into rural areas and dumping the sludge onto fields. This may cause major health concerns. Other methods of disposal may include incineration, adding chemicals or dumping into landfills. However, concerns about contaminants, runoff, air pollution, tipping fees, and rising transportation costs have resulted in cities and municipalities seeking alternative and more efficient methods to handle the removal of wastewater biosolids.